This invention relates to video inspection apparatus having an optical system carriage movable adjustably along X (horizontal) and Z (vertical) axes above a transparent object stage or work table, which is movable along a Y (horizontal) axis disposed at right angles to the X and Z axes, and beneath which table a substage collimator system is adjustable along another X axis simultaneously with the X axis adjustment of the optical system carriage.
Heretofore, typical video inspection systems of the type described have employed an object stage or work table mounted on a base for adjustment along respective X and Y axes which extend at right angles to each other, and generally beneath a downward viewing optical system carried by a slide that is mounted for vertical adjustment on a Z axis. In addition to such typical systems, systems capable of conducting substantially larger measurements are often formed as part of a gantry arrangement which supports the optical system and its vertically movable slide. Typically in such system a large bridge structure is supported on two large linear bearings which support the bridge for motion solely in a Y direction relative to a stationary object. Upon the bridge is mounted a linear slide which is adjustable on the bridge in an X direction, and which carries for vertical adjustment thereon the optical system slide. In this manner the optical system can be positioned over a desired X, Y location.
Among the advantages of the present invention over such prior art systems is the fact that the measurement range in the vertical Z direction can be extended substantially, while offering certain precision advantages. For example, having the X axis in a fixed relationship to the measurement plane of the optical system at any height Z within the measurement volume, provides better consistency and reduces the inaccuracy effects of pitch, roll, and yaw of the associated linear slide mechanisms.
Accordingly, it is an object of this invention to provide an improved, compact video inspection apparatus of the type described which utilizes an object stage or work support that moves on a linear slide only in one direction (the Y direction), while the slide or carriage which is mounted for movement in the X direction, and which supports thereon the optical system, is movable vertically in the Z direction simultaneously with the entire optical system.
A further object of this invention is to provide an improved video inspection system of the type described in which the object stage or work support is mounted on a base for movement only in one direction (the Y direction), while a yoke mechanism, which is mounted for vertical movement on the base relative to the work support, has mounted thereon a slide or carriage which is movable in an X direction on the yoke, and which carries an associated optical system that is mounted for movement with the carriage in the X and Z directions relative to the work support.
Still another object of this invention is to provide an improved, compact video inspection apparatus of the type described wherein a substage collimator is mounted beneath the transparent work support or object stage for adjustment with the optical system in the X direction, thereby to maintain the collimator in registration with the optics head of the optical system.
Another advantage of this invention is that it includes an optical system carriage that is adjustable horizontally in an X direction on a yoke that in turn is adjustable vertically in a Z direction, thereby to achieve precise Z motion for the optical system.
Still a further object of this invention is to provide an inspection apparatus of the type described in which an optical system carriage, which in the X direction, is connected by a cable to a substage collimator to transmit movement of the optical system carriage to the substage collimator.
A transparent work-supporting slide is mounted on a base for adjustment horiziontally thereon in a Y direction. A yoke is supported for vertical movement in a Z direction on a pair of cylindrical columns which project upwardly from the upper surface of the base. A carriage which is mounted on the face of the yoke for horizontal adjustment in an X direction carries a lens system having in its lower end an objective lens mechanism which faces the transparent work support, and which has in its upper end a video camera for receiving an image from the objective lens mechanism. A substage collimator supporting arm is mounted in the base beneath the transparent work support for horizontal adjustment in the X direction. The forward end of the arm extends beneath the transparent work support and has therein a source of collimated light, which registers with the objective lens mechanism and is disposed to illuminate the underside of a workpiece mounted on the transparent work support. A system of cables connects the optical system carriage to the substage collimator arm so that the carriage and arm are made to shift in unison in the X direction, thereby maintaining the collimated light source always in registry with the objective lens of the optical system.